Ring-shaped or plate-like element and method for producing same

ABSTRACT

A ring-shaped or plate-like element, in particular for a metal-sealing material-feedthrough, for example for devices which are subjected to high pressures, such as igniters for airbags or belt tensioning devices, includes a feedthrough opening, whereby the feedthrough opening is located substantially in the center of the ring-shaped or plate-like element and whereby the ring-shaped or plate-like element has a thickness. The ring-shaped or plate-like element has a relief region in the area of the feedthrough opening. Further, the ring-shaped or plate-like element in the relief region has at least one thickness which is reduced by the height of the relief region and which is selected so that the feedthrough opening can be punched out of the ring-shaped or plate like element having the reducing thickness.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ring-shaped or plate-like element, inparticular for a metal-sealing material-feedthrough, in particular fordevices which are subjected to high pressures, for example igniters forairbags or belt tensioning devices, as well as a method of utilizationof such a metal-sealing material-feedthrough.

2. Description of the Related Art

Metal-sealing material-feedthroughs are already known in various formsfrom the current state of the art. Metal-sealing material-feedthroughsare to be understood to be vacuum-tight fusions of sealing materials,especially glasses, glass ceramics or synthetics in metals. The metalsfunction hereby as conductors. We refer you in this context torepresentative documentation U.S. Pat. No. 5,345,872 and U.S. Pat. No.3,274,937. Feedthroughs of this type are common in electronics and inelectrical engineering. The material used for sealing, especially glassserves hereby as an insulator. Typical metal-sealingmaterial-feedthroughs are constructed such that metallic internalconductors are sealed into a pre-formed sintered glass component,whereby the sintered glass component or the glass tube is sealed into anouter metal component with the so-called base body which is formed by aring-shaped or plate like element. Preferred applications formetal-sealing material-feedthroughs of this type are, for example,ignition devices. One area of application is in air bags or belttensioning devices in motor vehicles. In this case the metal-sealingmaterial-feedthroughs are a component part of an ignition device. Theentire ignition device includes in addition to the metal-sealingmaterial-feedthrough an ignition bridge, the explosive agent as well asa metal shrouding which tightly encloses the ignition mechanism. Eitherone or two, or more than two metallic pins may be inserted through thefeedthrough. In a preferred embodiment with one metallic pin the housingis grounded, in a preferred two-pin embodiment one of the pins isgrounded.

Metal-sealing material-feedthroughs, especially for igniters for airbagsor belt tensioning devices which distinguish themselves in that thefeedthrough opening for the metal pins is punched out of the base bodyhave become known from US 2006/0222881 A1, US 2004/0216631, EP-A-1 455160, US 2007/0187934 A1 and U.S. Pat. No. 1,813,906. During theproduction of the base bodies from a strip stock having a thickness inthe range of between 1 mm and 5 mm, preferably 1.5 mm and 3.5 mm,especially between 1.8 mm to 3.0 mm, more especially preferably between2.0 mm to 2.6 mm the openings are punched through the entire thicknessof base body D by means of a punching process, according to US2007/0187934 A1. The metal pin in the sealing material is embedded intothe opening punched into the base body across the entire thickness ofthe base body which is in the aforementioned range. Moreover, thefeedthrough opening in feedthroughs with more than one pin is arrangedoff-center according to US 2007/0187934 A1.

According to US 2007/0187934 A1 punching sheet metal has a multitude ofdisadvantages. One disadvantage is that when punching a strip stock, forexample sheet metal of the base body, a great amount of material wasteoccurs.

An ignition device for a pyrotechnic protective device has become knownfrom DE 10 2006 056077 A1 which has a casing for positioning the currentfeedthrough of the metal pin and means to avoid a relative movementbetween casing and metal pin. As in the case of US 2007/0187934A1 thebase body is also punched from a sheet metal, for example a strip stock.Moreover, the feedthrough openings were arranged off-axis, as in US2007/0187934A1.

EP 1 491 848 A1 shows a current feedthrough with a centrally locatedfeedthrough opening for a pin-type conductor. The production method forthe feedthrough opening is not described and it extends over the entirethickness of the base body.

Especially in metal-sealing material-feedthroughs with two metal pinsand an off-center opening the problem arises that the off-center openingresults in a weakening of the glazing.

What is needed in the art is to avoid the described disadvantagesaccording to the current state of the art and to cite in particular abase body in the form of a ring-shaped or plate-like element for ametal-sealing material-feedthrough which can be produced with lessermaterial waste than is the case in the current state of the art, inparticular also in a cold forming process. Moreover, to produce the basebody should be especially simple.

SUMMARY OF THE INVENTION

The present invention provides a plate-like element which forms the basebody for a metal-sealing material-feedthrough that includes afeedthrough opening which is located substantially in the center of theplate-like element, whereby the plate-like element has a thickness (D)and whereby a relief region is provided in the region of the feedthroughopening in the plate-like element. The thickness of the plate-likeelement is reduced in the area of the feedthrough opening by the reliefregion, for example so that the feedthrough opening can be punched outthrough the ring-shaped or plate-like element in the area of the reliefregion. Punching out the opening provides a base body which isespecially easy to produce.

If the thickness of the entire ring-shaped or plate-like element is, forexample, 4 millimeters (mm), then a reduced thickness DR can be providedin the area of the feedthrough opening with the assistance of a reliefregion which may, for example, be punched out of a cold-formed materialby means of a punch. If the height HF of the relief region is forexample 1.5 mm then, at a thickness DR of 4 mm a reduced thickness DR of2.5 mm results in the region of the ring-shaped or plate-like element inwhich the feedthrough opening is to be produced. The reduced thicknessDR of 2.5 mm permits even with a hard or respectively rigid material—asused in the case of cold forming the base body—punching out of thefeedthrough opening in the region of the reduced thickness.

According to the present invention, the thickness (D) of the ring-shapedor plate-like element may be reduced by the relief region by between 20%and 60%, for example between 30% and 50%.

In order to make the ring-shaped or plate-like element compatible withthe currently used turned components it is provided that thickness D ofthe ring-shaped or plate-like element is in the region of 3.5 to 6 mm.In order to ensure punchability in the region of the feedthrough openingthe reduced thickness is, for example, in the range of 1.5 mm to 4.5 mm,or between 2.0 mm to 3.0 mm. Due to the compatibility it is possiblethat components produced by means of forming, in particular coldforming, and punching according to the present invention can be used inairbag igniters as replacements for components produced by turningwithout having to substantially change the production method.

The ring-shaped or plate-like element may consist of steel, for examplehigh grade steel with a copper content in the range of 1 weight % to 5weight %, for example between 2 weight % to 4 weight %. A material ofthis type allows for the plate-like element, or respectively the basebody, to be produced through reshaping, especially through cold forming,for example from a wire material. Hereby a piece is initially cut off asteel wire with the above stated copper content and is then brought intothe desired shape by means of forming, for example compression. This isonly possible if the material possesses a certain elasticity which isachieved through the stated copper content. The material is heavilycompressed or respectively compacted through the described reshaping, inparticular cold forming process. The material of the plate-like bodydoes not only have to be workable through forming, in particular coldforming, but must also guarantee reliability in laser welding.

Surprisingly it has been found that a steel, in particular a high gradesteel with a copper content of 1 weight % to 5 weight %, combines thesetwo conflicting characteristics, namely on the one hand the sufficientelasticity for reshaping, in particular cold-forming, and on the otherhand sufficient rigidity, or respectively flexural strength in order towithstand the high extraction forces or respectively the high ejectionforce under load, as can occur in a metal-sealing material-feedthroughin an igniter.

The formed, in particularly cold formed, ring-shaped or plate-likeelement has a substantially round or circular outer shape due to theround or circular outer contour of the substantially cylindrical wire.In order to achieve the previously described values of ejection forcefor the metal pin in the metal-sealing material-feedthrough, thefeedthrough opening is arranged so that they include means to avoid arelative movement of sealing material and base body. This is achievedfor example in that protrusions are provided in the feedthrough openingor in that it, for example, has a substantially conical progression.

The previously described ejection force which is characteristic formetal-sealing material-feedthroughs is that force which must be appliedin order to eject the sealing material which is placed in the opening ofthe metal-sealing material-feedthrough from the feedthrough. The levelof the ejection force may be determined either hydrostatically ormechanically. If the ejection force is determined mechanically then thesurface of the sealing material is acted upon by a punch whereby thesurface of the punch which presses upon the sealing material is smallerthan the surface of the sealing material.

Alternatively, the ejection force may be measured hydrostatically. Inthe case of a hydrostatic measurement the sealing material is acted uponby a hydrostatic pressure, for example water pressure and is thenmeasured, whereby the sealing material is expelled from the feedthroughopening by the application of hydrostatic pressure.

In addition to the inventive ring-shaped or plate-like element, thepresent invention also provides a metal-sealing material-feedthroughwith a ring-shaped or plate-like element being the base body, wherebythe metal pin of the metal-sealing material-feedthrough is glazed intothe feedthrough opening of the ring-shaped or plate-like element withthe assistance of a sealing material.

For this purpose the metal pin is first fused into the sealing materialwhich may, for example, be a glass plug. Then, the glass plug is placedtogether with the metal pin into the feedthrough opening. The glass andmetal ring, in this case the ring-shaped or plate-like element areheated, so that after cooling the metal shrinks onto the sealingmaterial—in this case the glass plug.

The metal pin may include means to avoid relative movements. These canespecially advantageously include local expansions and/or constrictionsof the metal pin diameter in the region of the glazing. In the simplestscenario this is achieved by ripples in the metal pin which can, forexample, be produced by rolling the metal pin over suitable embossingtools. Other suitable forms and production methods are obviously alsocovered by the invention.

A metal-sealing material-feedthrough is, for example, cited whereby twometal pins are provided. Since, according to the present invention, thefeedthrough opening in the plate-like element is located essentially inthe center, both metal pins are curved. While one of the metal pins ispassed through the feedthrough opening insulated in the glass plug, theother metal pin is, for example, in the embodiment of a grounded pin andis conductively connected with the base body.

The inventive metal-sealing material-feedthrough is advantageouslyutilized in ignition devices of any desired design. For example, anignition device of this type can be provided for a pyrotechnicprotective device, especially for an airbag or a belt tensioning device.A pyrotechnic protective device of this type includes a metal-sealingmaterial-feedthrough in accordance with the current invention, as wellas a cap connected with the base body of the metal-sealingmaterial-feedthrough, whereby a propellant is encased between themetal-sealing material-feedthrough and the cap. The ignition device withthe inventive metal-sealing material-feedthrough can be utilized in gasgenerators, for example in hot gas generators, cold gas generators andhybrid generators. As stated above, preferred areas of application aredevices for pyrotechnic protective systems, for example airbags and belttensioners. A plate-like body, for a metal-sealing material-feedthroughis produced, for example, from a glass plug by reshaping.

Other applications of the inventive ring-shaped or plate-like elementare also covered by the invention. An additional application of thepresent invention is, for example, use of a pressure sensor as afeedthrough element.

In a method to produce a metal-sealing material-feedthrough byreshaping, a blank, for example of a wire-shaped material, is providedand the blank is subjected to processing so that a feedthrough-openingcan be incorporated into a ring-shaped or plate-like element createdfrom the blank, such as through punching. The processing of the blank orrespectively providing the blank with a shape may occur through onlyforming, for example, cold-forming. The process steps of the method canbe carried out in varying sequence.

One possible sequence without limitation thereto includes the followingprocess steps:

-   -   A blank in the form of a wire-shaped material is provided.    -   The blank is formed, by means of compressing, for example        cold-formed, whereby the relatively geometric dimensions are        changed, resulting in the plate-like element with an essentially        round outside contour.    -   A relief region is incorporated into the plate-like element.    -   After incorporation of the relief region in the plate-like        element—which results in that the plate-like element has a        lesser thickness in the region of the through-opening than the        thickness of the plate-like element, especially the base        body—the through-opening is produced in the region of reduced        thickness with the assistance of a punching process.

The relief region may be incorporated into the blank or the ring-shapedor plate-like element, or respectively the base body in that the blankor the ring-shaped or plate-like element is pressed against a punch. Dueto the pressure of the punch the material of the blank or thering-shaped or plate-like element which is, for example steel, such ashigh grade steel with a copper component of 1 to 5 weight % coppersurrounds around the punch. In this manner a relief bore or respectivelya relief region can be incorporated into the blank or the ring-shaped orplate-like element by means of the punch. Alternatively it is possiblenot to press the blank or the ring-shaped or plate-like element againsta punch, but instead press a punch against one side of the blank or thering-shaped or plate-like element. Due to the pressure this results inthat the material of the plate-like body is pushed out on the sideopposite the side on which the pressure is exerted. The result of thisprocess is again the production of a relief region.

In addition to the relief region as previously described an additionalopening can be incorporated on the side opposite the relief region, forexample a conical opening by means of forming or respectively reshaping,in particular cold-forming.

After providing the relief region, or respectively the relief regionand/or the additional opening, a punching tool is applied in the area ofthe relief region or respectively the additional opening and thefeedthrough opening is produced by means of punching. The thickness ofthe ring-shaped or plate-like element is reduced in the region of thethrough-opening which is to be punched, for example to values from 1.5mm to 4.5 mm.

A conically tapering opening may, for example, be produced withoutcutting with the assistance of the reshaping process and the punchingtool.

The advantage of the illustrated method is that the production of thering-shaped or plate-like element which finds use in a metal-sealingmaterial-feedthrough occurs essentially at the same time interval in alldifferent process steps. This means that the step of forming, inparticular cold-forming, the step of incorporating the relief opening orrespectively the relief region or respectively the additional opening,as well as the step of punching the through-opening into the ring-shapedor plate-like element requires essentially the same amount of time. Inthis manner it is possible—starting with a wire like material—to producea ring-shaped or plate-like element with a through-opening essentiallyat the same pace at different work stations, that is the work stationfor cold forming, the work station for producing the relief opening andthe work station for punching. If it is necessary, like for example inthe current state of the art, to produce the bore in a machined or coldformed ring-shaped or plate-like element not by means of a punchingprocess but by means of a drilling process, then the drilling processrequires a much longer time than reshaping, due to which the productionof a ring-shaped or plate-like element requires at least double thetime, compared to the described reshaping method.

An additional advantage of the inventive ring-shaped or plate-likeelement is that with the described production method no, or at most verylittle, material waste occurs. Therefore, it can be produced veryefficiently.

As stated previously, the plate-like element may consist of steel, suchas high grade steel with a copper content in the range of 1 weight % to5 weight %, for example between 2.0 weight % to 4 weight %. A materialof this type allows for the ring-shaped or plate-like element, orrespectively the base body to be produced through reshaping, for examplefrom a wire material. Hereby a piece is initially cut off a steel wirewith the above stated copper content. In an additional step it isbrought into the desired shape by means of reshaping or respectivelythrough compression into the form of the plate-like element. This isonly possible if the material possesses a certain elasticity which isachieved through the stated copper content. The material is heavilycompressed or respectively compacted through the described reshaping.

However, the material does not have to be formable only through forming,in particular cold forming, but in applications, for example for airbagigniters, it must also enable secure retention of the sealing materialin the feedthrough opening. A measure for this, particularly when usedin an igniter, are the ejection forces which act mechanically upon thesealing material. There are a multitude of industrial standards for thelevel of the ejection forces. They range, for example, from 1350 bar or1360 bar to above 1500 bar, above 1600 bar and 1750 bar to 2000 bar or2500 bar or even 3000 bar. The cited values are pressure datacorresponding to the ejection forces and are measured hydrostaticallythrough the previously described method. When utilized as igniters theycorrelate with the relevant expulsion pressures.

Moreover the material must also guarantee reliable laser welding whichis a conventional method in order to attach the ignition cap.

It has been shown that the relief region not only enables thepunchability of the feedthrough opening. The reduction in thickness ofthe ring-shaped or plate-like element in the relief region can alsofacilitate a local deflection of the element during pressurization, forexample through the explosion pressure. The inventors recognized thatthis deflection does not have to be negative, but that instead theextraction resistance of the sealing material in the feedthrough openingcan even be increased, especially if the feedthrough opening possessesthe described means to prevent the relative movement.

This can be explained as follows: If the relief region and therefore therelief opening is located on the side of the element facing away fromthe pressure (i.e. on the underside), the pressure which for exampleoccurs on ignition of the igniter, but also during measuring of theextraction forces, acts on the entire top side of the element. Amongother factors the deflection of the element is dependent on the rigidityand the thickness of the material. In the area outside the relief regionthe material in an inventive element is compacted and thick, so that infact no deflection can occur. In the area of the reduced thickness inthe relief region a local deflection may however occur which leads to acompression of the material on the top side and to stretching on itsunderside. This results in that the feedthrough opening tends to indentin the upper region (that is the side facing the pressure) and to expandon the underside. If the sealing material (and preferably the metal pinin it) is in the feedthrough opening, a lateral pressure is exertedvertical to the surface of the feedthrough opening and thereby theglazed region of the sealing material, and at the same time upon theglazed in metal pin. This local compression pressure can lead to anoteworthy increase in the ejection forces of the sealing material fromthe feedthrough opening. This increase can be further increased in thatthe feedthrough opening has a larger diameter in the upper region (ofthe indentation) than in the lower region (of the expansion). Thedifferent diameters represent the means to avoid the relative movementand are realized through a step or a conical progression of thefeedthrough opening.

Moreover, the reduction of the thickness of the ring-shaped orplate-like element in the relief region can improve the weldability ofthe element with additional elements, for example with the cover cap ofigniters or pressure sensors. The reduction in thickness of the elementin the relief region causes the element to have a peripheral ring-shapedarea which is thicker compared to the relief region. When producing, forexample, an ignition device or a pressure sensor a metal pin is normallyglazed into the feedthrough opening on the ring-shaped or plate-likeelement. Likewise, a second conductor can be connected to the bottom ofthe element. A cover cap is normally welded to the outer circumferenceof the element. When welding on the cover cap, heat is inevitablyintroduced into the element. Care must be taken here that the glass asthe sealing material is not damaged. The peripheral area which isqualified by the relief region has a larger surface which can againradiate the introduced heat, thereby reducing the temperature load onthe sealing material. This ring-shaped area therefore functions as awelding edge during the welding process. Due to the simplifiedweldability, rejects in further processing of the element into the endproduct can be reduced and the process stability increased.

In addition to the described method for the production of thering-shaped or plate-like element the ring-shaped or plate-like elementcan initially be produced as described above in a method to produce ametal-sealing material-feedthrough with a ring-shaped or plate likeelement as base body. Subsequently, a metal pin is fused into a sealingmaterial which may, for example, be a glass plug. Then, the glass plugis placed together with the metal pin into the feedthrough opening. Theglass and the metal ring, in this case the ring-shaped or plate-likeelement are heated, so that after cooling the metal shrinks onto thesealing material—in this case the glass plug.

A method for the production of a metal-sealing material-feedthrough isfurther provided according to the present invention wherein two metalpins are provided. Since, according to the present invention, thefeedthrough opening in the plate-like element is located essentially inthe center, both metal pins are curved. While one of the metal pins ispassed through the feedthrough opening insulated in the glass plug, theother metal pin is, for example, in the embodiment of a grounded pin andis conductively connected with the base body, for example throughbrazing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIGS. 1A-1 d illustrate a ring-shaped or plate-like element according tothe present invention;

FIGS. 2 a-2 c illustrate a ring-shaped or plate-like element accordingto the current state of the art;

FIGS. 3 a-3 c illustrate a metal-sealing material-feedthrough accordingto the present invention;

FIGS. 4 a-4 c illustrate a metal-sealing material-feedthrough accordingto the current state of the art;

FIGS. 5 a-5 d illustrate a method to produce a ring-shaped or plate-likeelement according to the present invention; and

FIGS. 6 a-6 b illustrates comparison of the phase lines in ametallurgical section of a ring-shaped or a plate-like body produced byreshaping and produced by machining.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIGS. 1 a-1 c,there is shown a ring-shaped or plate-like formation or elementaccording to the present invention which essentially is utilized as thebase body for a metal-sealing material-feedthrough. As shown in the topview in FIG. 1 b, ring-shaped or plate-like element 1 has essentiallycircular outer contour 3. Ring-shaped or plate-like body 1 is produced,for example, by a reshaping process, such as a cold-forming process, forexample from a wire. Hereby, a piece is first cut from the wire and issubsequently transformed through a reshaping process, for examplethrough compression into the spherical or circular form illustrated inFIG. 1 b in a top view and FIG. 1 c three-dimensionally from backside14.

Following this, relief region 5 is provided into reshaped component 1 bymeans of a punch. When providing the relief region with a punch thereshaped material surrounds the punch.

The sequence of the process steps is only exemplary. Alternatively therelief region could first be incorporated and the ring-shaped elementthus provided with the relief region through reshaping, such ascold-forming to transform it into the required shape.

The height or respectively thickness of the relief region which is alsoessentially circular as shown in the top view from the rear in FIG. 1 bequals HF.

The thickness of the entire ring-shaped element which is obtainedthrough reshaping equals D. The material therefore is weakened in theareas where the feedthrough opening is essentially placed centralrelative to rotational axis R of the ring-shaped body, so that the solidmaterial through which feedthrough opening 10 in ring-shaped element 1must be punched equals merely DR. Thickness D of the ring-shaped bodyis, for example, reduced by between approximately 20% and 60%, orbetween approximately 30% and 50% through incorporation of the reliefregion. If one single relief region with a height or respectivelythickness HF is provided, then the height or respectively thickness HFis between approximately 20% and 60%, or between approximately 30% and50% of thickness D of the ring-shaped or respectively plate-like body.Thickness D of the ring-shaped or plate-like element may vary between3.5 mm to 6 mm and thickness DR of the region to be punched out between1.5 mm and 4.5 mm. If ring-shaped element 1 is utilized in ametal-sealing material-feedthrough, then a metal pin in a sealingmaterial, for example in a glass plug is inserted in feedthrough opening10. The glass plug is then in contact with the walls of the feedthroughopening. In order to avoid pushing the metal pin which was glazed into aglass plug out of feedthrough opening 10, even at high pressures meansare provided to prevent a relative movement from front side 12 ofplate-like element 1 to rear side 14. In the present embodiment of thepresent invention this is achieved in that the feedthrough openingtapers conically over at least one region 20, as illustrated in FIG. 1d.

In comparison to FIGS. 1 a-1 c, FIGS. 2 a-2 c show a ring-shaped orplate-like element according to the current state of the art.Ring-shaped or plate-like element 100 according to the current state ofthe art is machined or is obtained in the form of a reshaped component,for example from a cut off wire segment. Feedthrough opening 110 isincorporated in component 100 for glazing of the metal pin. In contrastto FIG. 1 a, feedthrough opening 110 incorporated into the ring-shapedor plate-like body produced for a metal-sealing material feedthroughbase body is placed off-center, in other words offset relative torotational axis R. Due to the off-center arrangement and very greatthickness DS through which the feedthrough opening must be punched it isnot possible to punch the feedthrough opening from cold-formedring-shaped or plate-like element 100. Feedthrough opening 110 is ratherincorporated into the base body having thickness DS of for example 4.5mm by drilling. Compared to a punching procedure this is a substantiallymore expensive procedure, in particular, a bore of this type requires amuch longer time than the production of the ring-shaped or plate-likecomponent or respectively element with the assistance of reshaping.Drilling out is necessary in particular because the material is heavilycompressed through the reshaping process, so that simple punching out isnot possible. A top view of plate-like element 100 according to thecurrent state of the art is shown in FIG. 2 b, and a three-dimensionalview in FIG. 2 c. Feedthrough opening 110, located off-center is clearlyrecognizable.

Referring now to FIGS. 3 a-3 c, there is illustrated utilization of aplate-like element according to FIGS. 1 a-1 c according to the presentinvention in a metal-sealing material-feedthrough, for example forairbag ignition devices or belt tensioning devices. Hereby FIG. 3 aillustrates a section according to FIG. 1 a, FIG. 3 b a top viewaccording to FIG. 1 b and FIG. 3 c an exploded view according to FIG. 1c from rear 14. Identical components as shown in FIGS. 1 a and 1 c carrythe same identification numbers.

Ring-shaped element 1 is clearly recognizable. Moreover, relief region 5is recognizable, which for example is punched out of the cold-formedring-shaped or plate-like element 1 by means of a punch. Above thepunch, feedthrough opening 10 with conical progression 20 which ispunched from the remaining material with thickness DR can be seen.Whereas in the embodiment of the present invention illustrated accordingto FIGS. 3 a-3 c the conical form is incorporated over the entire lengthof the feedthrough opening, it is possible that in an alternativeembodiment the conical form extends only over a section of the length ofthe feedthrough opening which means that the feedthrough openingpossesses two segments—one conical and one adjacent thereto which is notconical. The conical segment may be produced, for example, throughreshaping or respectively forming and the non-conical segment throughpunching.

Alternately it is also possible to produce the relief region by means ofa separate machining process, for example through drilling and/ormilling. It is equally possible to combine the processes, for example inthat the relief region is first pre-formed during reshaping in thepreviously described processes and is then transformed into its finishedform through separate machining methods, such as milling and/ordrilling. The term “relief region” in the sense of the current inventionis therefore used regardless of the type and method in which it wasproduced. It includes in particular the production through reshaping andthe production through machining processes such as milling and/ordrilling. Therefore it can also be used synonymously with relief bore.

The ring-shaped or plate-like element serves as the basis for ametal-sealing material-feedthrough with a total of two metal pins 50,52. While metal pin 50 is fed through the ring-shaped or plate-like basebody 1 from the front side to the rear side, insulated in sealingmaterial 60—in this case a glass material which however can also beglass ceramics or ceramic materials—second metal pin 52 serves as groundpin. For this purpose, second metal pin 52 is connected directly withring-shaped or plate-like body 1. Metal pin 50 as well as metal pin 52is curved. The curvature of both metal pins is identified with 54 and 56respectively and is clearly recognizable.

Metal pin 50 is moreover provided with means 62 on metal pin 50directly, which engage into the glass plug, thereby preventing the metalpin being pushed out of glass plug 60 into which the metal pin isglazed—even at high pressures.

Glazing of metal pin 50 into sealing material 10 occurs through melting.As soon as the metal pin is fused into the sealing material the glassplug is inserted into feedthrough opening 10 together with the metalpin. Then, the glass plug, together with the ring-shaped or plate-likeelement, that is the base body, is heated so that after cooling themetal of the ring-shaped or plate-like element shrinks onto the sealingmaterial, in this case the glass material, as previously in theproduction of the glass plug whereby the metal pin is inserted into theglass plug. Grounded metal pin 52 is connected conductively with theplate-like element, for example through brazing. The welding location isidentified with 70.

Referring now to FIG. 3 b there is shown a top view from rear side 14 ofan inventive metal-sealing material-feedthrough. Clearly seen in the topview is central feedthrough 10 in ring-shaped or plate-like element 1.Moreover, curved metal pin 50 and 52 respectively are clearlyrecognizable. Especially on metal pin 50 it can be clearly seen that themetal pin is offset, that is bent at end 72 relative to center R of theplate-like base body. This also applies to metal pin 52. The curved pinsare also clearly visible in the view in FIG. 3 c. The illustration inFIG. 3 c of the entire metal-sealing material-feedthrough shows inparticular also welding region 70 of the grounded pin as well as reliefregion 5 in the ring-shaped or plate-like base body. It ischaracteristic for a metal-sealing material-feedthrough with aring-shaped or plate-like element as a base body according to thepresent invention which has relief region 5 that glazing 20 of the metalpin in the base body occurs only over a partial region, namely only overthickness DR of the feedthrough opening and not over entire thickness Dof the base body. In contrast hereto, glazing in a metal-sealingmaterial-feedthrough according to the current state of the art occurs,as shown in FIGS. 4 a-4 c, over entire thickness DS of the ring-shapedor plate-like formed base body, as illustrated in FIGS. 2 a-2 c. Glazing160 is again implemented with metal pin 150 in feedthrough opening 110of the ring-shaped or plate-like element. Whereas metal pin 150 isinserted into glazing 160, grounded pin 152 is welded onto ring-shapedor plate-like base body 100. Both pins—metal pin 150 and grounded pin152 are straight.

Referring now to FIG. 4 b, there is shown a top view of a metal-sealingmaterial-feedthrough according to FIG. 4 a. Identical components as inFIG. 4 a carry the same reference numbers. As can be clearly seen, metalpins 150, 152 do not have a curved structure. FIG. 4 c is an explodedview drawing of back side 114 of the component according to FIG. 4 a-4b.

Referring now to FIG. 5 a, there is shown the various stations of anembodiment of the production process for a plate-like element accordingto the present invention. In the first station blank 1010 is separatedor respectively cut from wire like material 1000. In the second step,that is in the second station to which the severed blank is transported,in one production step the blank is formed by compressing, for examplecold-formed to the point where the outside dimensions conform to theoutside dimensions which the ring-shaped or plate-like element that isto be manufactured must have. The relative geometric dimensions arehereby altered, whereby in the current example the blank becomes widerdue to compressing. In the following third station reshaped plate-likeelement 1020 is pressed against punch 1040 with pressure 1030. Due tothe pressure with which the ring-shaped or plate-like element is pressedagainst the punch, the material of the ring-shaped or plate-like elementsurrounds the punch. The material in the region of the punch is therebyremoved from the plate-like element and the plate-like element withrelief opening or respectively relief region 1050 shown in the fourthstation remains. The description of the sequence of process steps ismerely exemplary. A relief opening in the blank could also be producedfirst, followed by subsequent reshaping. It would also be possible toimplement the reshaping step in station 2 and the incorporation of therelief region for example through forming in station 3 in one singlestation, for example station 2. Station 3 would then be eliminated.

Due to the relief region, thickness D of the plate-like element has beengreatly reduced in region 1060 of the ring-shaped or plate-likeelement—that is to thickness DR. Thickness D of the ring-shaped orplate-like element is hereby reduced by between approximately 20% and60%, or between approximately 30% and 50%, which means that thickness DRis between 80% and 40%, for example between 70% and 60% of thickness D.Then, in a fifth process step punching tool 1060 is inserted into therelief opening and conical feedthrough opening 1070 is for examplepunched through the ring-shaped or plate-like element. Essentially, thering-shaped or plate-like element with relief opening and feedthroughopening results as demonstrated in the fifth station. The inventivemethod distinguishes itself in that for each of the cited stations, thatis for severing the wire-like base material, reshaping, provision of therelief opening or respectively the relief region and punching of thefeedthrough opening through the plate-like element with reducedthickness, essentially the same time is taken for each process step.This allows for the inventive method to be highly automated.

Referring now to FIGS. 5 b and 5 c there are shown two methods which arepossible in principle for incorporation of the relief region and/or ofadditional openings through forming. In FIG. 5 b, as in FIG. 5 aring-shaped or plate-like element 1020 is pressed against punch 1040 inthe third step, so that the material surrounds the punch and from this arelief opening and/or an additional opening results. Alternatively itwould be possible, as shown in FIG. 5 c, that the plate-like base body1020 is not pressed against punch 1040, but vice versa, punch 1040 ispressed against ring-shaped or plate-like base body 1020. Then, due tothe pressure on the side of the ring-shaped or plate-like body oppositethe punch, the material is expelled. The result again is the ring-shapedor plate-like element with relief region and/or an additional opening.

Referring now to FIG. 5 d there is shown a method wherein additionallyto relief region 1050, additional opening 2100 is incorporated onopposite side 2050 before thereby resulting remaining thickness RD ispunched through. For identical components as in FIGS. 5 a-5 c the samereference numbers are used. The additional opening which can be conicalis, for example, provided through forming, for example by means of apunch. It is possible, however not necessary if in the second stationduring reshaping relief region 1050 and on side 2050 opposite reliefregion 1050 additional, for example conical, opening 2100 is alreadyprovided, for example also through forming. This has the advantage thatonly one process step is required. By incorporating the additionalopening only remaining thickness RD which is located between additionalopening 2100 and relief region 1050 has to be punched through in thepunching station in order to provide the feedthrough opening into whichthe metal pin is glazed. As can be clearly seen, feedthrough opening2200 has two regions—one conical region or respectively conical opening2100, as well as punched out region 2300. With the alternative methodtherefore, the conical opening can be produced especially easily, namelythrough forming, for example in the reshaping step. Obviously, as in themethod in step 5 a in station 2, the blank could first be compressed andthe relief bore and/or additional opening be produced following thisstep. Remaining thickness RD which is to be punched through amounts hereto between 10% and 70% of total thickness D, for example betweenapproximately 30% and 50% of total thickness D of the ring-shaped orplate-like element.

Referring to FIG. 6 a there is shown a metallurgical section through aring-shaped or plate-like element 1 produced in a reshaping and punchingprocess, as illustrated in FIG. 1 a. Identical components as shown inFIG. 1 a carry the same identification numbers. As can be seen from themetallurgic section according to FIG. 6 a, ring-shaped or plate-likeelements 1 produced according to the inventive method are identifiedthrough structure-/flow-lines 1500 which were bent in region 1600 due tothe reshaping process.

In contrast to this, FIG. 6 b illustrates component 100 produced bymeans of machining, which is in particular a turned part. Shown againare structure-/flow lines 2000. Structure-/flow lines 2000 areessentially parallel and point into the same direction as the bar stockfrom which ring-shaped or respectively plate-like component 100 wasproduced according to the state of the art, as shown in FIG. 6 b.Feedthrough opening 110 is bored out of component 100.

The invention cites a method for the first time with which a plate-likeelement is to be produced in a simple manner and distinguishes itselfthrough compatibility with the metal-sealing material-feedthroughaccording to the state of the art, thus enabling installation inconventional ignition devices or respectively airbags. In particular itis possible with the present invention to produce metal-sealingmaterial-feedthroughs for qualified already existing igniter deviceswith greater material savings. In particular a method is also citedwherein a conical feedthrough opening which is one embodiment of afeedthrough opening with means to avoid a relative movement can beproduced in an especially simple manner. Moreover, a method is citedwherein a plate-like element can be produced in a simple manner.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. A base body for a metal-sealingmaterial-feedthrough subject to high pressures in an igniter for one ofan airbag and a belt tensioning device, said base body for saidmetal-sealing material feedthrough being an element formed by a processof cold forming and having one of a ring-shape and a plate-like shape,the element comprising a feedthrough opening located substantially in acenter of the element and extending from a front side of the elementtoward a rear side of the element, and a relief region in an area ofsaid feedthrough opening at said rear side of the element and located ona side of said base body distal to said high pressures of said igniter,said relief region having a diameter that is greater than a diameter ofsaid feedthrough opening in a region adjacent to said relief region, theelement having an entire thickness (D) and at least one reducedthickness (DR) in said relief region, said at least one reducedthickness (DR) being said entire thickness (D) reduced by a height (HF)of said relief region and selected so that said feedthrough opening isformed by the process of punching said base body through said at leastone reduced thickness (DR).
 2. The base body according to claim 1,wherein said entire thickness is reduced in said relief region bybetween approximately 20% and 90%.
 3. The base body according to claim2, wherein said entire thickness is reduced in said relief region bybetween approximately 30% and 70%.
 4. The base body according to claim3, wherein said entire thickness is reduced in said relief region bybetween approximately 40% and 50%.
 5. The base body according to claim1, wherein at least one of said entire thickness of the element isgreater than approximately 3.5 millimeters (mm), said reduced thicknessis in a range between approximately 1.5 mm and 4.5 mm and a remainingthickness is in a range between approximately 0.35 mm and 4.2 mm.
 6. Thebase body according to claim 5, wherein at least one of said entirethickness of the element is in a range between 3.5 mm and 6.0 mm, saidreduced thickness is in a range between 2.0 mm and 2.6 mm and saidremaining thickness is in a range between 1.1 mm and 3.0 mm.
 7. The basebody according to claim 1, wherein the element is formed from steel. 8.The base body according to claim 7, wherein the element is formed of ahigh grade steel with a copper content of between 1 and 5 weight %. 9.The base body according to claim 8, wherein said copper content isbetween 2 and 4 weight %.
 10. The base body according to claim 1,wherein the element has an essentially round outer contour formed fromone of a forming process and a reshaping process.
 11. The base bodyaccording to claim 10, wherein said round outer contour is a circularouter contour and said forming process is a cold-forming process from awire-like element.
 12. The base body according to claim 11, wherein saidfeedthrough opening comprises a means to avoid relative movements, saidmeans being at least partially an essentially conical progression. 13.The base body according to claim 1, wherein said element has ametallurgic structure with a plurality of serpentine shaped stress linessurrounding said relief region and said feedthrough opening.
 14. A basebody for a metal-sealing material-feedthrough subject to high pressuresin an igniter for one of an airbag and a belt tensioning device, saidbase body for said metal-sealing material feedthrough being an elementformed by a process of cold forming and having one of a ring-shape and aplate-like shape, the element being formed of a high grade steel with acopper content of between 1 and 5 weight % and having a feedthroughopening located substantially in a center of the element and extendingfrom a front side of the element toward a rear side of the element and arelief region in an area of said feedthrough opening at said rear sideof the element, said relief region having a diameter that is greaterthan a diameter of said feedthrough opening in a region adjacent to saidrelief region, the element having an entire thickness (D) and at leastone reduced thickness (DR) extending between an edge of said reliefregion and said front side of said element, said at least one reducedthickness (DR) being said entire thickness (D) reduced by a height (HF)of said relief region and selected so that said feedthrough opening isformed by the process of punching said base body through said at leastone reduced thickness (DR).
 15. A metal-sealing material-feedthroughsubject to high pressures in an igniter for one of an airbag and a belttensioning device, the metal-sealing material-feedthrough comprising: abase body defining an element formed by a process of cold forming andhaving one of a ring-shape and a plate-like shape, the element having afeedthrough opening at a location substantially in a center of saidelement and extending from a front side of said element toward a rearside of said element and a relief region formed in an area of saidfeedthrough opening at said rear side of said element, said reliefregion having a diameter that is greater than a diameter of saidfeedthrough opening in a region adjacent to said relief region, theelement having an entire thickness (D) and at least one reducedthickness (DR) extending between an edge of said relief region and saidfront side of said element, said at least one reduced thickness (DR)being said entire thickness (D) reduced by a height (HF) of saidcold-formed relief region and selected so that said feedthrough openingcan be formed by the process of punching said base body through said atleast one reduced thickness (DR); a sealing material positioned in saidfeedthrough opening; a first metal insulated pin at least partly in saidsealing material and positioned in said feedthrough opening; and asecond metal pin, said second metal pin being a grounded pinconductively connected with said base body and not extending into saidfeedthrough opening.
 16. A base body for a metal-sealingmaterial-feedthrough subject to high pressures in an igniter for one ofan airbag and a belt tensioning device, said base body for saidmetal-sealing material feedthrough being an element formed by a processof cold forming and having one of a ring-shape and a plate-like shape,the element comprising a feedthrough opening located substantially in acenter of the element and extending from a front side of the elementtoward a rear side of the element, and a relief region in an area ofsaid feedthrough opening at said rear side of the element and located ona side of said base body distal to said high pressures of said igniter,said relief region being formed by a reshaping process and having adiameter that is greater than a diameter of said feedthrough opening ina region adjacent to said relief region, the element having an entirethickness (D) and at least one reduced thickness (DR) in said reliefregion, said at least one reduced thickness (DR) being said entirethickness (D) reduced by a height (HF) of said relief region andselected so that said feedthrough opening is formed by the process ofpunching said base body through said at least one reduced thickness(DR), wherein said cold forming process, said reshaping process and saidpunching process provide said element with a metallurgic structureproviding corresponding visible indicia surrounding said relief regionand said feedthrough opening.